Looks like a timer that you screw into the shutter button. It has the same thread works as the end of a shutter release cable. Of course your XG-1 probably has a timer on it and this will not be much use, but on older model cameras (pre-timer) it could be fun.

A self-timer. It should screw into the shutter release button. Set by rotating the dial or a lever that may not show in this picture and push a button. It can come in very handy if the camera does not have a built-in self-timer. I have one that looks somewhat similar that I use with a Hasselblad and on large format lenses that it will fit.